AB CompactLogix 1769-L32E

[Ones_Zeros]

hey guys I've been having an issue with my HMI not communicating with the PLC. The PLC is a CompactLogix L32E and It happens at random times.

when i go to the site i see the "MS" and "NS" lights on the PLC flashing red

I have a managed switch inside my PLC cabinet and to correct this all i have to do is reboot the managed switch then the computer will start communicating with the PLC again. I have to do this several times a day.

I have replaced the managed switch in the PLC cabinet with a new switch.

I have read were someone had to re-flash the PLC controller to correct the issue.

have any of you guys had this similar issue?

thanks

 

[Steve Bailey]

Look into how frequently the HMI is trying to refresh the data it gets from the PLC. Trying to refresh faster than the PLC can handle can result in degraded performance or even communications lockup. Also, make sure that all of the PLC variables that the HMI is trying to read actually exist. Dealing with the error messages associated with trying to read from or write to a non-existent PLC tag also slows things down.

 

[Ones_Zeros]

OK thank you I will check these out